1. Field of the Invention
The present invention relates to a technique for updating information in a database connected to a network.
2. Description of the Background Art
In recent years, there has been a trend to implement all communication networks using IP (Internet Protocol). An IMS (IP Multimedia Subsystem) has been proposed that implements integrated multimedia services by implementing, using IP, all services that have been provided so far by a fixed network, mobile communication, broadcasting, etc.
For the IMS, there is a technique described in Japanese Patent Application National Publication (Laid-Open) No. 2005-515712, for example. Japanese Patent Application National Publication (Laid-Open) No. 2005-515712 discloses a method and a system for changing a contract in an IMS such that appropriate services can be guaranteed even after a profile of a subscriber has been changed.
Meanwhile, as a scheme for updating information on a subscriber in an IMS, there is a so-called first win scheme. When a system updates information with the first win scheme, the system uses an identification number to which “1” is added every time data is updated.
An apparatus which requests for an update to a database periodically acquires an identification number from the database. The apparatus transmits the identification number together with an update request to the database. When the database receives the update request, the database compares the received identification number with a current identification number which is held thereby. Then, only when both identification numbers match, the database updates data and adds “1” to the current identification number. By this sequence, the identification number is updated.
Thus, after that, even when a data update request with an identification number, which was obtained prior to the above-mentioned update, are transmitted to the database from another apparatus, the identification number does not match the identification number of the database. In this case, a data update requested by the another apparatus is rejected and thus an update is not performed.